This application claims priority to Japanese Patent Application No. 2000-1790 filed on Jan. 7, 2000, the disclosure of which is incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a luminescence controlling apparatus, a luminescence apparatus, an image reading apparatus and an image forming apparatus.
2. Description of Related Art
For example, a Japanese Patent Laid-open Publication No.
H5-242870 proposes a luminescence control technology in which a plurality of pairs of electrodes are arranged such that each pair is disposed on a circumference of a discharge lamp along the axial direction of the discharge lamp, and the number of electrodes to which voltage is impressed is selected in order to control the luminescence amount of the discharge lamp.
However, the aforementioned luminescence controlling apparatus has drawbacks such that the structure is complicated since the apparatus has many electrodes for controlling the luminescence of the discharge lamp, which results in an increased manufacturing cost. Furthermore, the luminescence amount can only be changed stepwise by selecting the number of electrodes.
It is an object of the present invention to provide a luminescence controlling apparatus and a luminescence apparatus which are simple in structure and can perform a continuous and fine luminescence control.
It is another object of the present invention to provide a luminescence controlling apparatus and a luminescence apparatus which has a write-in function to a photosensitive member or the like by partially performing an ON/OFF luminescence control during the electric discharge.
It is still another object of the present invention to provide an image reading apparatus equipped with a luminescence apparatus which can perform a continuous and fine luminescence control as a light source for irradiating an original image.
It is still yet another object of the present invention to provide an image forming apparatus equipped with a luminescence apparatus which can partially perform an ON/OFF luminescence control during the electric discharge, as a light source for exposing a photosensitive member.
According to a first aspect of the present invention, a luminescence controlling apparatus includes a rare gas pipe in which rare gas is sealed, the rare gas pipe being equipped with a pair of electrodes, a power supply for impressing voltage to the pair of electrodes, an electric charge absorption member disposed in the rare gas pipe to absorb electrons generated during electric discharge of the rare gas pipe caused by impressing voltage to the pair of electrodes, and a controller for controlling a luminescence amount of the rare gas pipe by adjusting a quantity of the electrons absorbed by the electric charge absorption member.
With this luminescence controlling apparatus, electrons (electric charges) generated during the electric discharge of the rare gas pipe are absorbed by the charge absorption member like a grid line disposed in the rare gas pipe. Therefore, by adjusting the amount of electrons to be absorbed by the electric charge absorption member, the amount of energy of the electrons colliding with the rare gas atoms can be adjusted, which in turn enables an adjustment of the excitation energy of the fluorescent substance layer formed on the inner peripheral surface of the rare gas pipe. Consequently, although the apparatus is simple in structure, the luminescence amount of the rare gas pipe can be finely controlled in an analog manner.
According to the second aspect of the present invention, a luminescence controlling apparatus includes a rare gas pipe in which rare gas is sealed, a pair of electrodes formed in the rare gas pipe, a power supply for impressing voltage to the pair of electrodes, an electric charge absorption member for absorbing current which flows through the pair of electrodes when voltage is impressed by the power supply, and a controller which controls whether or not the rare gas pipe emits light by switching whether or not the electric charge absorption member absorbs current.
In this luminescence controlling apparatus, by switching whether or not the electric charge absorption member absorbs the current when the rare gas pipe is discharging, the excitation energy of the fluorescent substance layer is controlled, which in turn enables an ON/OFF control of the luminescence operation.
According to the third aspect of the present invention, a luminescence apparatus includes a rare gas pipe in which rare gas is sealed, a pair of external electrodes formed on an outer peripheral surface of the rare gas pipe, and a conductive member disposed in the rare gas pipe, wherein the conductive member is capable of sending electrons out of the rare gas pipe, the electrons being generated during electric discharge of the rare gas pipe caused by impressing voltage to the pair of electrodes.
With this luminescence apparatus, the electrons generated at the time of electric discharge of the rare gas pipe is sent from the rare gas pipe since the conductive member is disposed in the rare gas pipe. Therefore, the energy amount of electrons colliding with the rare gas atoms can be adjusted by adjusting the amount of electrons sending from the rare gas pipe.
According to the fourth aspect of the present invention, a luminescence apparatus includes a rare gas pipe in which rare gas is sealed, a pair of external electrodes formed on an outer peripheral surface of the rare gas pipe and a plurality of conductive members disposed at predetermined intervals in an axial direction of the rare gas pipe so as to contact the pair of external electrodes.
With this luminescence apparatus, it is possible to switch whether or not current is absorbed at the time of electric discharge of the rare gas pipe for every plural conductive members disposed so as to contact the external pair of electrodes, which enables an ON/OFF control of the luminescence operation.
According to the fifth aspect of the present invention, an image reading apparatus for reading an original image includes a light source for irradiating the original image, wherein the light source includes a rare gas pipe in which rare gas is sealed, a pair of external electrodes formed on an outer peripheral surface of the rare gas pipe and a conductive member disposed in the rare gas pipe, the conductive member being capable of sending electrons generated during electric discharge of the rare gas pipe caused by impressing voltage to the pair of electrodes out of the rare gas pipe, and a solid image taking element which obtains image data based on incident light from the original image.
With this image reading apparatus, a variable control of the irradiation amount to the original image can be continuously performed at the time of reading the original image.
According to the sixth aspect of the present invention, an image forming apparatus includes a photosensitive member, and a light source for exposing the photosensitive member corresponding to an image data, wherein the light source includes the rare gas pipe in which rare gas is sealed, a pair of external electrodes formed on an outer peripheral surface of the rare gas pipe and a plurality of conductive members which contact the pair of external electrodes and are arranged at predetermined intervals in an axial direction of the rare gas pipe.
With this image forming apparatus, a writing to the photosensitive member can be controlled every interval of the conductive member corresponding to the image data.
Other objects and the features of the present invention will be apparent from the following detailed description of the invention with reference to the attached drawings.